Autodeposition compositions
AssigneeHenkel Corporation
InventorBrian D. Bammel
Life of this patent
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Abstract
Autodeposition compositions for polymeric coatings of reduced gloss are prepared using resins having at least one hydroxy group and at least one epoxy group per molecule, a low temperature crosslinker and a high temperature crosslinker. The low temperature crosslinker forms a reactive prepolymer that may be subsequently mixed or emulsified with a high temperature crosslinker to form an autodeposition composition. Alternatively, a hybrid crosslinking agent may be utilized which contains both free isocyanate groups reactive at a relatively low temperature with the resin and at least one functional group capable of reacting with the resin only at a relatively elevated temperature. When deposited and cured, the resulting coating has a matte finish that is resistant to surface defects.
Claims47
A cured autodeposited coating comprising the reaction product of:
- (a) a resin containing one or more epoxy groups and one or more hydroxy groups per molecule;
- and
- (b) one or more crosslinking agents, wherein at least one crosslinking agent contains two or more free isocyanate groups per molecule capable of reacting with the hydroxy groups of the resin at a first temperature and at least one crosslinking agent contains one or more functional groups per molecule capable of reacting with said resin only at a second temperature which is greater than the first temperature.
An autodeposition composition comprising:
- a. water;
- b. a reactive prepolymer which comprises a reaction product of (i) a resin containing at least one epoxy group and at least one hydroxyl group reactive with a free isocyanate group at a first temperature, and (ii) a low temperature crosslinking agent containing free isocyanate groups reactive with said hydroxyl group at said first temperature;
- and
- c. a high temperature crosslinking agent capable of reacting with said reactive prepolymer only at a second temperature which is higher the first temperature.
An autodeposition composition comprising:
- a. water;
- and
- b. a reactive prepolymer comprising a reaction product of (i) a resin containing at least one functional group reactive with a free isocyanate group at a first temperature and (ii) a hybrid crosslinking agent containing both at least two free isocyanate groups capable of reacting with said resin at said first temperature and at least one functional group capable of reacting with said resin only at a second temperature higher than said first temperature, wherein the reactive prepolymer contains in unreacted form at least one of the functional groups capable of reacting with said resin only at said second temperature.
Dependencies are inferred from the claim text.